Deformed General Relativity and Quantum Black Holes Interior

Arruga, Denis; Achour, Jibril Ben; Noui, Karim

doi:10.48550/arxiv.1912.02459

Cited by 12 publications

(19 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Secondly, in App. A we consider a quite generic deformation of the diffeomorphism constraint for the vacuum model and show that, under the requirement of forming a closed algebra, the only allowed modification is a global multiplicative function, in agreement with results presented in [38]. This points out that the deformation of the diffeomorphism constraint is trivial and does not provide additional freedom for further corrections in the Hamiltonian.…”

Section: Discussionsupporting

confidence: 83%

“…Results in App. A generalize previous studies that point out that the requirement of anomaly freedom only admits trivial modifications of the diffeomorphism constraint [38].…”

Section: Vacuumsupporting

confidence: 61%

“…Thus, the dependence of the modified Hamiltonian on the radial curvature component K r is bound to be linear and, therefore, holonomy corrections for this variable will not be allowed. Replacing now the results ( 40)-( 43) in equation (38), we obtain the following condition for f 0 :…”

Section: A Scalar Fieldmentioning

confidence: 97%

“…Expressions ( 40)-( 42) and ( 45) completely solve equation (38). Replacing all the results in the other anomaly (39), every term vanishes except for the coefficients of (E r ) ′ and φ ′ , which provide the following two additional restrictions:…”

Section: A Scalar Fieldmentioning

confidence: 99%

“…Nonetheless, this approach suffers equally from the lack of covariance, as analyzed in [32]. On the other hand, the consistent constraint deformation approach has already been applied to several spherical models, both in vacuum and coupled to different matter fields [32][33][34][35][36][37][38], leading to promising results. In particular, the effective line element corresponding to the holonomy-corrected constraints might present a signature change when approaching the classical singularity.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Holonomy and inverse-triad corrections in spherical models coupled to matter

Alonso-Bardaji,

Brizuela

2020

Preprint

View full text Add to dashboard Cite

Loop quantum gravity introduces two characteristic modifications in the classical constraints of general relativity: the holonomy and inverse-triad corrections. In this paper, a systematic construction of anomaly-free effective constraints encoding such corrections is developed for spherically symmetric spacetimes. The starting point of the analysis is a generic Hamiltonian constraint where free functions of the triad and curvature components as well as non-minimal couplings between geometric and matter degrees of freedom are considered. Then, the requirement of anomaly freedom is imposed in order to obtain a modified Hamiltonian that forms a first-class algebra. In this way, we construct a family of consistent deformations of spherical general relativity, which generalizes previous results in the literature. The discussed derivation is implemented for vacuum as well as for two matter models: dust and scalar field. Nonetheless, only the deformed vacuum model admits free functions of the connection components. Therefore, under the present assumptions, we conclude that holonomy corrections are not allowed in the presence of these matter fields.

show abstract

Section: Discussionsupporting

confidence: 83%

“…Results in App. A generalize previous studies that point out that the requirement of anomaly freedom only admits trivial modifications of the diffeomorphism constraint [38].…”

Section: Vacuumsupporting

confidence: 61%

Section: A Scalar Fieldmentioning

confidence: 97%

Section: A Scalar Fieldmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Holonomy and inverse-triad corrections in spherical models coupled to matter

Alonso-Bardaji,

Brizuela

2020

Preprint

View full text Add to dashboard Cite

show abstract

Effective quantum dust collapse via surface matching

Münch¹

2021

Class. Quantum Grav.

View full text Add to dashboard Cite

The fate of matter forming a black hole is still an open problem, although models of quantum gravity corrected black holes are available. In loop quantum gravity (LQG) models were presented, which resolve the classical singularity in the centre of the black hole by means of a black-to-white hole transition, but neglect the collapse process. The situation is similar in other quantum gravity approaches, where eternal non-singular models are available. In this paper, a strategy is presented to generalise these eternal models to dynamical collapse models by surface matching. Assuming (1) the validity of a static quantum black hole spacetime outside the collapsing matter, (2) homogeneity of the collapsing matter, and (3) differentiability at the surface of the matter fixes the dynamics of the spacetime uniquely. It is argued that these assumptions resemble a collapse of pressure-less dust and thus generalises the Oppenheimer–Snyder–Datt model, although no precise model of the matter has to be assumed. Hawking radiation is systematically neglected in this approach. The junction conditions and the spacetime dynamics are discussed generically for bouncing black hole spacetimes, as proposed by LQG, although the scheme is approach independent. Further, the equations are explicitly solved for the recent model Bodendorfer et al (2019 Class. Quantum Grav. 36 195015) and a global spacetime picture of the collapse is achieved. The causal structure is discussed in detail and the Penrose diagram is constructed. The trajectory of the collapsing matter is completely constructed from an inside and outside observer point of view. The general analysis shows that the matter is collapsing and re-expanding and crosses the Penrose diagram diagonally. This way the infinite tower of Penrose diagrams, as proposed by several LQG models, is generically not cut out. Questions about different timescales of the collapse for in- and outside observers can be answered.

show abstract

Bouncing compact objects. Part I. Quantum extension of the Oppenheimer-Snyder collapse

Achour

Brahma

Uzan

2020

J. Cosmol. Astropart. Phys.

Self Cite

View full text Add to dashboard Cite

This article proposes a generalization of the Oppenheimer-Snyder model which describes a bouncing compact object. The corrections responsible for the bounce are parameterized in a general way so as to remain agnostic about the specific mechanism of singularity resolution at play. It thus develops an effective theory based on a thin shell approach, inferring generic properties of such a UV complete gravitational collapse. The main result comes in the form of a strong constraint applicable to general UV models : if the dynamics of the collapsing star exhibits a bounce, it always occurs below, or at most at the energy threshold of horizon formation, so that only an instantaneous trapping horizon may be formed while a trapped region never forms. This conclusion relies solely on i) the assumption of continuity of the induced metric across the time-like surface of the star and ii) the assumption of a classical Schwarzschild geometry describing the (vacuum) exterior of the star. In particular, it is completely independent of the choice of corrections inside the star which leads to singularityresolution. The present model provides thus a general framework to discuss bouncing compact objects, for which the interior geometry is modeled either by a classical or a quantum bounce. In the latter case, our no-go result regarding the formation of trapped region suggests that additional structure, such as the formation of an inner horizon, is needed to build consistent models of matter collapse describing black-to-white hole bounces. Indeed, such additional structure is needed to keep quantum gravity effects confined to the high curvature regime, in the deep interior region, providing thus a new challenge for current constructions of quantum black-to-white hole bounce models. 4 In this model, the authors use the light-like version of the junction conditions discussed in Ref. [82]. 5 See Ref.[91] for a similar model.

show abstract

Deformed General Relativity and Quantum Black Holes Interior

Cited by 12 publications

References 0 publications

Holonomy and inverse-triad corrections in spherical models coupled to matter

Holonomy and inverse-triad corrections in spherical models coupled to matter

Effective quantum dust collapse via surface matching

Bouncing compact objects. Part I. Quantum extension of the Oppenheimer-Snyder collapse

Contact Info

Product

Resources

About